Electric heating – Inductive heating – With heat exchange
Reexamination Certificate
2000-05-26
2002-02-26
Leung, Philip H. (Department: 3742)
Electric heating
Inductive heating
With heat exchange
C219S622000, C219S624000, C219S627000, C219S667000, C126S246000, C126S375100, C099SDIG014
Reexamination Certificate
active
06350972
ABSTRACT:
BACKGROUND OF THE INVENTION
A major difficulty faced by owners of food delivery establishments is maintaining the temperature of hot foods, such as pizza, sandwiches, Chinese food, and the like, during delivery of the hot food from the kitchen to the customer. In colder climates, the difference in temperature between the heated food and the environmental temperature may be considerable, and thus result in significant cooling of the food, which may affect food quality and taste during consumption.
Traditionally, pizza delivery establishments have addressed this problem by inserting the heated pizza into a box, usually formed from cardboard, and then into a receptacle or bag formed of thermal insulating material where the pizza would be kept during the delivery process. However, such thermal insulating pizza bags are limited in their ability to maintain the desired temperature by factors, such as delivery time and environmental temperature.
Still other heated food delivery systems utilize integrated electric energy heaters which require relatively lengthy preheating period, e.g., up to two hours, before the food delivery container is available for the first heated delivery. As can be appreciated, a significant amount of energy and time is required to accomplish the foregoing, neither of which is conducive for fast food establishments, such as pizza restaurants. Also, in order to have an adequate amount of heated delivery containers ready during periods of peak delivery, the user would have to anticipate the number of heated delivery containers that would be needed and then commence the heating procedure well in advance of the actual use of the heated delivery container. Of course, if the user over estimates the number of heated delivery containers eventually required, costly energy is wasted in order to heat the unused containers. In the alternative, if the user underestimates the number eventually needed, the required lead/preheat time would preclude the user from obtaining a properly heated delivery container in the short time period required to satisfy today's consumers.
In addition to the significant amount of energy and lead time required to preheat conventional food delivery containers, the space required by conventional pizza bag delivery systems is quite extensive due to peak time demand. For example, U.S. Pat. No. 4,816,646 to Solomon et al. discloses a typical conventional receptacle for maintaining the desired cooked temperature of food during delivery from the kitchen to the consumer. Solomon et al. utilizes a conventional electric resistance heater.
FIG. 4
of the Solomon et al. patent illustrates a plurality of such receptacles mounted on shelves in a “ready” condition. Thus, in order to have an adequate number of heated delivery containers ready during peak demand, a substantial panel of the food establishment's precious cooking space must be dedicated to preheating heated delivery bags.
Another deficiency of conventional heated food delivery containers, particularly pizza bags, is that they are designed to have a single food storage cavity for transporting the food product in a heated condition. Although many food establishments have attempted to accompany more than one food product into each container during peak demand, it results in inadequate interior temperatures within the container and, thus, reduces the quality of the transported food product. A need has arisen for an efficient bag which can carry more than one food container and yet maintain uniform heat throughout the bag so that one container is not hotter than another.
Many conventional systems for heating conventional food delivery containers, such as pizza bags, rely on heating the food delivery container or a heating member which is then inserted into the food delivery container for a predetermined time period at a predetermined temperature. These conventional heating systems fail to provide a method for self-regulation of the heating system unless a regulator, like a thermostat, is added to the system. With such conventional heating systems, a food delivery container that has been heated, but has not cooled to ambient temperature, is still reheated during the subsequent heating cycle for the same predetermined time period as during the initial heating cycle. The use of such predetermined time period for subsequent heating cycles results in unnecessary expenditure of energy and time. Certainly, in today's competitive business atmosphere both foregoing commodities must be utilized more efficiently than is provided by conventional food delivery containers, especially pizza delivery containers.
In addition to economy of time and energy, safety of the food service worker is a primary factor. As stated above, conventional food delivery containers, particularly pizza bags, rely on a predetermined time-period for heating the container. However, if the timer fails to deactivate the heating procedure, the temperature of the heating member will continue to rise. This result could not only destroy the food delivery container, but also creates a significant safety hazard to the food service personnel. The nature of the use of food delivery containers necessitates a great deal of actual handling by the food service worker under harried and hurried conditions. A need exists for a food delivery container that not only provides a shorter heating period, but also provides a fail-safe mechanism to prevent the container from over heating and still allow safe handling by the food service worker after the heating cycle.
A need continues to exist for a heated food delivery container that is able to maintain a heated storage area at an elevated temperature relative to ambient temperature, uniformly throughout the delivery container. A need also exists for a heat retentive delivery container that (1) utilizes less time to heat, (2) is self-regulating in its energy consumption during the heating process to require less energy and less time during subsequent heating cycles, and (3) has a fail-safe mechanism to prevent heating higher than a predetermined temperature. A need also continues to exist for a heated food delivery container that requires less preparation time and storage area than conventionally available heated delivery containers. An additional need exists for a system, which is capable of substantially reducing the lead time required to preheat a heated delivery container to its preferred transport temperature. A further need exists for a system which is self-regulating with respect to energy consumption and length of time of activation.
The present invention pertains to a storage container for maintaining food items at a desired temperature during transport thereof. More particularly, this invention pertains to food storage/delivery containers which include a novel self-regulating heat induction system which only heats the delivery container to a predetermined temperature regardless of the initial temperature of the delivery container when it is heated or reheated by the system. The present invention provides a novel induction-based heated delivery container system, which is capable of heating delivery containers in substantially less time than conventional electric heater or phase change technology. Due to the substantially reduced preheating time required, the container systems according to the present invention are capable of heating more containers per energy generation station than conventional systems, thus substantially reducing the amount of kitchen space required for preparation and temporary storage of the delivery containers. Additionally, the present invention provides a unique heating system, which is capable of self-regulation, i.e., brings each reused container back up to transport temperature without having to heat for a complete preheating cycle, i.e., starts at the current temperature of the container and only utilizes the required amount of energy to heat the container to its predetermined transport temperature. This greatly reduces preheating time, allows for rapid reuse of
LaFevor Jack Wendell
Wright David Gregg
Aladdin Temp-Rite, LLC
Leung Philip H.
Ohlandt Greeley Ruggiero & Perle LLP
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